From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/sstep: Convert to scoped user access
Date: Tue, 10 Mar 2026 11:03:41 +0100 [thread overview]
Message-ID: <8f2d85bddacff18046096dc255fd94f6a0f8b230.1773137010.git.chleroy@kernel.org> (raw)
Commit 861574d51bbd ("powerpc/uaccess: Implement masked user access")
provides optimised user access by avoiding the cost of access_ok().
Convert single step emulation functions to scoped user access to
benefit from masked user access.
Scoped user access also make the code simpler.
Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
---
arch/powerpc/lib/sstep.c | 77 +++++++++++++++++-----------------------
1 file changed, 33 insertions(+), 44 deletions(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ac3ee19531d8..f0d6aa657c1a 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -329,20 +329,17 @@ __read_mem_aligned(unsigned long *dest, unsigned long ea, int nb, struct pt_regs
static nokprobe_inline int
read_mem_aligned(unsigned long *dest, unsigned long ea, int nb, struct pt_regs *regs)
{
- int err;
+ void __user *uea = (void __user *)ea;
if (is_kernel_addr(ea))
return __read_mem_aligned(dest, ea, nb, regs);
- if (user_read_access_begin((void __user *)ea, nb)) {
- err = __read_mem_aligned(dest, ea, nb, regs);
- user_read_access_end();
- } else {
- err = -EFAULT;
- regs->dar = ea;
- }
+ scoped_user_read_access_size(uea, nb, efault)
+ return __read_mem_aligned(dest, (unsigned long)uea, nb, regs);
- return err;
+efault:
+ regs->dar = ea;
+ return -EFAULT;
}
/*
@@ -385,20 +382,17 @@ static __always_inline int __copy_mem_in(u8 *dest, unsigned long ea, int nb, str
static nokprobe_inline int copy_mem_in(u8 *dest, unsigned long ea, int nb, struct pt_regs *regs)
{
- int err;
+ void __user *uea = (void __user *)ea;
if (is_kernel_addr(ea))
return __copy_mem_in(dest, ea, nb, regs);
- if (user_read_access_begin((void __user *)ea, nb)) {
- err = __copy_mem_in(dest, ea, nb, regs);
- user_read_access_end();
- } else {
- err = -EFAULT;
- regs->dar = ea;
- }
+ scoped_user_read_access_size(uea, nb, efault)
+ return __copy_mem_in(dest, (unsigned long)uea, nb, regs);
- return err;
+efault:
+ regs->dar = ea;
+ return -EFAULT;
}
static nokprobe_inline int read_mem_unaligned(unsigned long *dest,
@@ -465,20 +459,17 @@ __write_mem_aligned(unsigned long val, unsigned long ea, int nb, struct pt_regs
static nokprobe_inline int
write_mem_aligned(unsigned long val, unsigned long ea, int nb, struct pt_regs *regs)
{
- int err;
+ void __user *uea = (void __user *)ea;
if (is_kernel_addr(ea))
return __write_mem_aligned(val, ea, nb, regs);
- if (user_write_access_begin((void __user *)ea, nb)) {
- err = __write_mem_aligned(val, ea, nb, regs);
- user_write_access_end();
- } else {
- err = -EFAULT;
- regs->dar = ea;
- }
+ scoped_user_write_access_size(uea, nb, efault)
+ return __write_mem_aligned(val, (unsigned long)uea, nb, regs);
- return err;
+efault:
+ regs->dar = ea;
+ return -EFAULT;
}
/*
@@ -521,20 +512,17 @@ static __always_inline int __copy_mem_out(u8 *dest, unsigned long ea, int nb, st
static nokprobe_inline int copy_mem_out(u8 *dest, unsigned long ea, int nb, struct pt_regs *regs)
{
- int err;
+ void __user *uea = (void __user *)ea;
if (is_kernel_addr(ea))
return __copy_mem_out(dest, ea, nb, regs);
- if (user_write_access_begin((void __user *)ea, nb)) {
- err = __copy_mem_out(dest, ea, nb, regs);
- user_write_access_end();
- } else {
- err = -EFAULT;
- regs->dar = ea;
- }
+ scoped_user_write_access_size(uea, nb, efault)
+ return __copy_mem_out(dest, (unsigned long)uea, nb, regs);
- return err;
+efault:
+ regs->dar = ea;
+ return -EFAULT;
}
static nokprobe_inline int write_mem_unaligned(unsigned long val,
@@ -1065,6 +1053,7 @@ static __always_inline int __emulate_dcbz(unsigned long ea)
int emulate_dcbz(unsigned long ea, struct pt_regs *regs)
{
+ void __user *uea = (void __user *)ea;
int err;
unsigned long size = l1_dcache_bytes();
@@ -1073,20 +1062,20 @@ int emulate_dcbz(unsigned long ea, struct pt_regs *regs)
if (!address_ok(regs, ea, size))
return -EFAULT;
- if (is_kernel_addr(ea)) {
- err = __emulate_dcbz(ea);
- } else if (user_write_access_begin((void __user *)ea, size)) {
+ if (is_kernel_addr(ea))
err = __emulate_dcbz(ea);
- user_write_access_end();
- } else {
- err = -EFAULT;
- }
+ else
+ scoped_user_write_access_size(uea, size, efault)
+ err = __emulate_dcbz((unsigned long)uea);
if (err)
regs->dar = ea;
-
return err;
+
+efault:
+ regs->dar = ea;
+ return -EFAULT;
}
NOKPROBE_SYMBOL(emulate_dcbz);
--
2.49.0
next reply other threads:[~2026-03-10 10:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-10 10:03 Christophe Leroy (CS GROUP) [this message]
2026-04-08 4:28 ` [PATCH] powerpc/sstep: Convert to scoped user access Madhavan Srinivasan
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